Variable traffic signal



April 10, 1928. 1,665,560 R. o. NELSON VARIABLE TRAFFIC SIGNAL FiledMay'16, 1925 2 She ets-Sheet 1 r 42 I 7 8a jflflniar B08591 0. IVE: $0M5 April 10, 1928.

R. o. NELSON YARIABLE TRAFFIC SIGNAL 'f7 .9% R '28 l .23 $4- 2Sheets-Sheet 2 jrzyfzfor B06597 Q/Va son PATENT, OFFICE.

ROBERT 6L,NELSON, OF PORTLAND, OREGON VARIABLE TRAFFIC SIGNAL.

Application and m 16, 1925. Serial No. 30,865.

This invention relates to traflic controlling and regulating devices,and the primary object is to provide an automatic signalling device atthe intersection of a main or arterial highway and a cross road whichordinarily accommodates a lesser amount of trafiic, whereby theright-of-way will be constantly maintained on the big way untll avehicle on the cross road approaches the intersection, whereupon thesignalling system will be reversed, by being actuated by such vehicle,to give it the right-of-way across the highway, after which theright-of-way sig-i na s again revert to the highway or main traiiic. Afurther object consists in providing means whereby the right-of-way willbe automaticall alternated for periods of, for instance, t irty' secondsto each road when trailie is constantly approaching the intersection onthe cross road. Still further and more specific objects will bedisclosed in the course of the following specification, reference beinhad to the accompanying drawings, w erein:

Figure 1 is a plan view of a street or road intersection, showing theposition of the tri ger switches in the cross road.

Figure 2 is a sectional elevation through one of the trigger switches.

Figure 3 is .a diagrammatic plan view showing the wiring and connectionsof the electrical control system.

Figure 4 is a plan view of a magnetic "switch employed in the circuitsystem.

Figures 5 and 6 are end and side. views, respectively, of theswitchshown in Figure 4. v

Figure .7 is a sectional line 7-7 in' Figure 4.

Figure 9 is an elevation of an alternator used in the device. r

Figures 8, 10, 11, 12, and 13 are sectional views as seen substantiallyon the respective lines- 8-8, 10-10, 11-11, 12-12, and 13-13, in Figure9.

. Referring to the drawingsmore particu larly and by referencecharacters A designates a north and south street or read, hereinafterreferred to as the highway, which is crossed by an east and west streetB, hereinafter designated as the cross road, and at r the middle pointof the intersection is a conventional signaling standard C, in the baseof which may be arranged the control box D. The signals may be of any ofthe well known types in which the Stop and v elevation on the HEISSUEDGo signs are electrically lighted and alternated so that when the signreads Stop in one direction it will read Go in the other or crossdirection, and vice versa. Thus in Figure 3 I have indicated signallamps R, R as the red or stop lamps for the highway, and these lamps arecircuitously connected with the lamps G, G, which are thegreen or Golamps of the cross road; while the R, R Stop lights for the cross roadare connected in circuit with and are simultaneously energized withgreen Go lamps G, G, which give the right-ofway to the highway traflic,and stop the cross road trafiic.

The circuit controlling mechanism (later to be described) which controlsthe two cir-' cuits to the lamps in the signal, is preferger switchesmay be greatly varied and modified but a preferred form is illustratedin Figure 2 and is substantially the same as the trigger switch shown inFigure 3 of my copending application for patent Ser. No. 695,- 596,which was filed on February 27, 1924, for automatic variable traiiicregulator. It consists, primarily, of a box or casing 13 which isimbedded in the street, and has a plate 10 pivotally secured therein, asat 11. Theswinging end of the plate 17 has a flange 12 which tends tokeep the box closed when the plate is. in its raised position. The plate17 is normally retained in an inclined or raised position as shown, by aspring 14, but when travelledover by the wheel of a vehicle, isdepressed to a flush or horizontal position where it steps. A pair ofswitch terminals 15 and 16 are respectively secured to the plate 10 andbox 13, and close together when the plate is depressed, and thus close acircuit through wires 17 and 18 which lead 30 the control box through asuitable conuit.

tBefor'e tracing the circuits in-an-d to the control box and'to thelighting group and trigger switches, the mechanistic mechani- 32. Asolenoid 23is mounted on the base and serves, when energized, to pull alever 24 down against the yielding tension of a spring 26.. When ,thesolenoid is de-energized, the spring 26 tends to restore the lever 24toits upper position, as shown in Figures 5 and 6. This upward movement isretarded, however, by an air check consisting of a pivoted cylinder 28in which operates a piston 27 which is connected-to the outer extremityof the lever 24. A second lever member '29 is arranged parallel with thelever 24, and, like the latter, is pivoted at its rear end to the wall31, while the forward ends of both lovers are guided by being slidablein vertical slots in the'wall 32. The lever 29 is yicldingly raised by aspring 33, and is depressed #by alaterally projecting finger 25 of thelever 24. WVhen the lever 29 is released by the finger25 it is retainedin its" lowered position by a bell crank catch member 37 which ispivoted on 32 and retained by a spring 38. When the lever 24 now returnsto its fullupward positions, it moves the member 37 to release the lever29, whereupon the latter may also return to its upward position. Theterminal of a wire 39 is mounted at the-'outer'end of the lever 29 sothat it will close a switch with a wire 43 the terminal of which isstationary on the wall 32. 39ris also a supply wire to the solenoid 23.The lever 24*is arranged to be retained in its lowered position by abell-crank hook member 34, which is retained in engagement by "a magnet35, supplied by wires 43 and 59, but Which is released by a. spring 36,when the magnet is de-energi'zed.

The alternator indicated in Figure 3 and shown more in detail in Figures8 to 13, inclusive, will now be described as follows: A shaft 4O isjournaledin suitable end brackets 40. A drum 50is rigidly secured on theshaft to rotate with it, and a drum 51 is rotatably mounted on theshaft. The drum 50 has a. ratchet wheel 49 adapted to be engaged by atiming unit or mechanism when a circuit is closed through the wires 43and 54. The timer T may be of any common and well known constructionwhich is capable of lifting and dropping an arm or dog 68 at regularintervals so as-to turn the ratchet wheel 49 the length of one tooth foreach elevation of the dog. A pawl 67 is brought to bear against theratchet wheel 49 by a magnet- 66 which is also placed in the circuit4354. It will thus be seen that the pawl 67 will prevent the reverserotation of the ratchet wheel when the latter or lug 70 or 71 on thedrum. As the with the lever 24 road trafiic to actuate being rotatedallow the wheel t sition when the timer is inactive and the circuit 43-54 is broken.

Within the drum 51 the shaft is enlarged as at 40 {Fig 11) and to it isfastened one end of a coil spring 69, the other or outer end of whichissecured tothe inner face of the drum. Now when the shaft is rotated,

by the drum 50, the spring 69 winds itself about the shaft. tionary,against the-rotatingtendency of the spring, by a pawl 72, which is heldagainst the periphery of the drum by a spring 73, and releasably engagesthe stop shaft 40 continues to rotate it will be evident that the springtension would soon become excessive, and-t0 relieve this tension(without reversing the drum) 1 provide the drum 50 with a pair ofdiametrically opposed tripping lugs 7 3 and 74, which at certainintervals in the movement of the drum 50 act against a projection 76 ofthe pawl 72, and releases the latter from the lugs 70, 71. To

prevent the drum 5,1.from returning too rapidly, when so released,Tprovide a small governor 78 which is operatively associated with thedrum through gears 77 and 52.

'VVhen the ratchet wheel 49 is freed from the timer T, the spring 69will reverse' the direction of the shaft and also the drum 50. Thisreverse movement iswchecked, however, by thearm 76 of the" pawl 72,which engages either of the teeth 74 or 73 to stop the drum 50 in aninitial position.

An essential F or primary alternator is mounted on the drum- 50 andconsists of a peripheral path 48448 (Figs. 9, 10) having alternatingconducting and non-conducting areas which rotate in contact withbrushes- 44 and 45,-which are yieldingly retained in contact with thepath by springs 47, and which are terminals for wires 42 and 41,respectively. The conducting areas 48 are supwires 48 from a member 46on the shaft 40, which in turn is supplied through its journal in thebracket 40 by the wire 54. The initial position of the drum is such thatthe terminal brush 45 will have contact with an intermediate point .onone of the areas 48. I The circuit wiring will now be set forth.

Wires 21 and 22 represent the power sup-" ply, which, for convenience:in tracing we can assume .to be negative in wire 22. When there is nocross therewill bea closed circuit through the elements 21, 54, 40 40,46, 48 48, 45, re, and 22, thus lighting the lamps R, R and G G andgiving a constant right-of-way to the traffic on the highway. Now whenan east or west bound vehicle approaches the intersection on the crossroad, it depresses initial popositive in wire 21, and

the switches E or F the plate 10 of the trigger switches E or F,

and in so doing closes a circuit between the wires 17 and 18, andenergizes the solenoid 23, via 39 and 18, resulting in the closing of acontact between the terminals 39 and 43 as above described; The wire 43now gives a negative supply to the. magnet 35 and the timer T of thealternator, and the wire 54 carries a positive charge to the timer andto the contact areas48. Thus the timer is actuated as soon as thecontact between 43 and 39 is made. A branch 59 of the wire 42 carries apositive charge, when the terminal 42 has contact with'48of thealternator, to the retention magnet 35, and consequently the magnet 35is'energiz'ed while 4339 is closed. When a circuit is closed throughwires 42, then the signal lampsG, G and R R are supplied, signalling theright-of-way to the highway traflic as 57 is the negativewire to all thelamps, and when the wire 41 is. charged then the opposite lamps G,- G,R, and R are energized, to signal the right-of-way to traflic on thecross road.

In order that a bell signal of short duration may be given, as theright-of-way is changed from one direction to theother, I provide athermal switch in each of the circuits of 41 and 42. Each of theseswitches is constructed so that it will break the circuits through wires63 and 64, to the bell 61, shortly after the current starts flowing in41 or 42. To avoid short circuits separate circuits are provided forthe/bell by way of a negative wire 62 to the wire' 57.

Having now described the construction and action of the device and itsvarious parts, it will be understood, that the right-.

of-way wall be constantly retained on the highway until approachingcross traffic has depressed. one of the trigger switches E or F. and fora brief period of time thereafter, such eriod bein half the length 0contact area 40 (Fi 10), thus permitting a steady flow of tra c on thehighway as long as possible, and shortly after the circuit 17-18 isclosed by a cross road vehicle, the right-of-way will be transferred tothe cross road, and the vehicle will be given ample time, to .cross thehighway.

'This time will of course, be determined by to render about fifteenseconds or,

'viding, however, that such modificationsa highway lamp circuit and across-road lamp circuit, a time controlled switch asso-- ciated withsaid circuits for alternately open ing and closing the same, said switchbeing normally idle in an initial position, so as to normally retain thehighway circuit closed and permit highway trafiic to cross theintersection, means actuated, by avehicle ap-,

proaching the intersection on the'cross road for actuating the switch soas to alternately de-energize the highway circuit and energize the crossroad circuit to successively signal the right-otway to the cross roadand highway, said means including the time controlled switch and beingoperative for automatically restoring the switch and the lamp circuitsto their initial conditions.

. 2. A street crossing signal system including a pair of signalcircuits, one circuit including a signalto indicate Stop and the otherto indicate Go, switching means nor;

mally maintaining the Go signal circuit closed and the Stop si nalcircuit open and movable through a cycle to first reverse and thenrestore to'normal the circuit conditions, normallyinactlve t1mecontrolled means for moving. said swltchmg means throu h its.

cycle, vehicle actuated means for rendering sa d tnnecontrolled meansactive, and means operated by the switch at the end of its cycle thetime controlled means again inactive.

3. A. street crossing signalling system including a pair of signalcircuits, one circuit including a signal to indicate Stop and the otherto indicate Go, switching means movable through a cycle for alternatelyenergizing said circuits,-normally inactive time controlled means formoving said switchin means through its cycle, vehicle actuate means forrendering said time controlled means active, and means including theswitch its for, restoring the time controlled means to its inactivecondition.

" 4. A street crossing signalling system includinga pair of signalcircuits, one cirthe other to indicate Go, switching means movablethrough a cycle for alternately energizin said circuits, normallyinactive-time control ed means for moving said switching means throughits cycle, vehicle actuated means for rendering said time controlledmeans active, and means 0 erated by the switch at the end of its timecycle, for rencuit including a signal to indicate Stop and flexing""iimc cnmrniicd nicnns again in- .i sheet crnssing signaiiing systeminsin n pair of signal circnitsynnc circuii; inciuciing a signal toindicate Stop and the c'tiicr i0 indicate G0, the G0 signal circnii;which is narmally closed and the Stow signal circuit open, a normallyinactive chime controlled switching means for successiveiy andaiiernately reversing the open ture,

ROBERT 0. NELSON

